Quite a few folks have been wondering about thrips applications, as cotton is still going into the ground, some growers are thinking about a second spray, and we've had cool rainy weather impeding cotton growth. We also collected some helpful data in 2024 from Lewiston-Woodville (Peanut Belt Research Station) simulating rainfall. Some considerations:

- In the northeast, use Hemi (spinetoroam) 3 oz + surfactant. Tobacco thrips in that area are resistant to acephate (Orthene). In the 2024 trial at Lewiston-Woodville, spinetoram was better than acephate, likely due to resistance

- Tim Bryant (VA Tech entomologist) found that 2025 western flower thrips adult numbers were higher than tobacco thrips in most southeast Virginia cotton fields. Hemi is a better product for Western flower thrips than acephate

-The only way to tell western flower thrips from tobacco thrips is using a microscope

- When tobacco thrips are not resistant to acephate, acephate is better than spinetoram. These data show that acephate at 6 oz (Orthene) was better than spinetoram (Radiant = Hemi) at 3 oz

- Don’t switch from acephate to Bidrin. They are both in the same chemical group called organophosphates. That means thrips that are resistant to acephate will also be resistant to Bidrin. This has already been shown shown in the Midsouth with tobacco thrips

- Resistance will likely move out of the northeast. Growers thinking about a re-spray should not use acephate again, but switch to Hemi, especially if they are unhappy with acephate efficacy

- Rain can wash away both acephate and spinetoram. In our 2024 study, these insecticides didn’t work as well when it rained up to 8 hours after spraying. Because we didn’t test what happens after 8 hours, we don’t know how long the spray needs to dry before rain to still work well

- Spinetoram washed off more from rain than acephate

- Rain can wash away insecticides, but it’s still better to spray than to wait. Even a little protection is better than none. This is especially true if the cotton isn’t growing and we don’t know when the field will be dry enough to spray again

- Cotton planted in May was, and is, at high risk for thrips, since they are dispersing into cotton

- Sprays at the 1st true leaf bud provide the highest yield return. Yield return for sprays is inconsistent once cotton reaches 2 leaves. Yield returns for sprays are rare once cotton reaches 4 leaves